Properties of IRT-14 (TEM-45), a newly characterized mutant of TEM-type beta-lactamases
| ISSN: | 1098-6596 0066-4804 |
|---|---|
| Přístupová URL adresa: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::70ad8a35d7ecd547b38e80d949eb5514 https://doi.org/10.1128/aac.41.2.374 |
| Rights: | OPEN |
| Přírůstkové číslo: | edsair.doi.dedup.....70ad8a35d7ecd547b38e80d949eb5514 |
| Autor: | M. Barthelemy, R Labia, L. Gilly, Rajagopal Krishnamoorthy, G. Paul, Maria Manuela M. Caniça |
| Rok vydání: | 1997 |
| Předmět: |
Molecular Sequence Data
Aztreonam Biology medicine.disease_cause Tazobactam beta-Lactamases Substrate Specificity chemistry.chemical_compound Clavulanic acid Escherichia coli polycyclic compounds medicine Pharmacology (medical) Enzyme kinetics Antibacterial agent Pharmacology Drug Resistance Microbial Sulbactam Drug Resistance Multiple Anti-Bacterial Agents Kinetics Infectious Diseases Biochemistry chemistry Mutation Isoelectric Focusing Research Article Moxalactam medicine.drug |
| Zdroj: | Antimicrobial Agents and Chemotherapy. 41:374-378 |
| ISSN: | 1098-6596 0066-4804 |
| Popis: | IRT-14 (TEM-45) is a new mutant TEM-type beta-lactamase that was isolated from clinical Escherichia coli P37 and that confers resistance to broad-spectrum penicillins with reduced sensitivity to beta-lactamase inhibitors. The MICs of amoxicillin alone and of amoxicillin combined with 2 micrograms of clavulanic acid or 2 micrograms of tazobactam per ml were 4,096, 2,048, and 1,024 micrograms/ml, respectively. The strain was susceptible to cephalosporins, aztreonam, moxalactam, and imipenem. The enzyme was purified to homogeneity, and values of the kinetic parameters Kcat, Km, and Kcat/Km were determined for different substrates. This enzyme, with a pI of 5.2, was found to have reduced affinity for broad-spectrum penicillins and cephalosporins. The values of 50% inhibitory concentrations of clavulanic acid, sulbactam, tazobactam, and brobactam are correlated with the higher KmS for substrates. The resistance of E. coli P37 to mechanism-based inactivators results from a higher level of production of the TEM-derived enzyme due to the G-to-T substitution at position 162 (G-162-->T) in the promoter region of blaTEM and from the structural modifications resulting from the Met-69-->Leu and Arg-275-->Gln substitutions that characterize IRT-14 beta-lactamase. |
| Databáze: | OpenAIRE |
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